Anatomical variability of the anterior cingulate gyrus and basic dimensions of human personality.

This study focused on investigating a possible relationship between interindividual variability in the morphology of the cingulate gyrus and behavioral styles. Using magnetic resonance images obtained from 100 healthy young volunteers (50 women and 50 men), we measured the surface area of the anterior cingulate gyrus and related it to the scores on the Temperament and Character Inventory. Anatomical data revealed that hemispheric asymmetry in the anterior cingulate gyrus surface area was very common (83% of cases) and that a prominent right anterior cingulate was more frequent in women than in men. In the correlational analysis, surface measurements of the right anterior cingulate gyrus accounted for a 24% score variance in Harm Avoidance. Both women and men with larger right anterior cingulate described themselves as experiencing greater worry about possible problems, fearfulness in the face of uncertainty, shyness with strangers, and fatigability. Furthermore, women reported overall higher scores in Harm Avoidance than men; these gender differences were largely explained by gender differences in the right anterior cingulate area in a covariate analysis. Our observations suggest that a large right anterior cingulate is related to a temperamental disposition to fear and anticipatory worry in both genders and that a higher prevalence of these traits in women may be coupled with a greater expansion of this brain region.